Muscular System Overview

Muscular System Overview

  • Types of Muscle Tissue:

    • Skeletal Muscle: Striated, voluntary, attached to bones, responsible for body movement, maintains posture, generates heat, limited regeneration.

    • Cardiac Muscle: Striated, involuntary, makes up the heart, has intercalated disks allowing coordinated contractions; no regeneration capacity.

    • Smooth Muscle: Non-striated, involuntary, found in hollow organs (e.g., digestive tract, blood vessels), contractions are not under conscious control.

Structure of Skeletal Muscle

  • Muscle Anatomy:

    • Origin: Attached to stationary bone.

    • Insertion: Attached to movable bone.

    • Body: Main part of the muscle.

  • Attachments: Skeletal muscles connect to bones via tendons, lubricated by synovial fluid, with bursae to aid movement.

  • Microscopic Structure: Composed of muscle fibers (myofibrils with thick and thin myofilaments, myosin and actin).

  • Contraction Mechanism: Based on the sliding filament model; relies on calcium ions and ATP.

Muscle Function

  • Movement: Muscles pull on bones to produce movement at joints.

  • Posture Maintenance: Tonic contractions maintain posture.

  • Heat Production: Muscle contractions generate heat, crucial for maintaining body temperature.

Muscle Fatigue and Recovery

  • Fatigue results from intense stimulation without sufficient rest, leading to ATP depletion and lactic acid buildup (oxygen debt).

Interaction with Other Body Systems

  • Involvement of Other Systems: The muscular system works alongside nervous (controls movement), respiratory (for oxygen supply), circulatory (blood flow), and skeletal systems (muscle attachment).

Muscle Contraction Types

  • Isotonic: Muscle changes length during contraction (concentric/ eccentric).

  • Isometric: Muscle tension increases without movement.

Effects of Exercise

  • Hypertrophy: Muscle growth due to regular exercise, increasing total mass.

  • Atrophy: Muscle shrinkage following inactivity (disuse atrophy).

  • Strength vs. Endurance Training:

    • Strength training increases the number of myofilaments, enhancing muscle mass.

    • Endurance training improves cardiovascular efficiency without significant hypertrophy.